CaK Full Disk 16th February

[marktownley]

Hi All.

It's a case of chasing the gaps at the moment with what seems like wall to wall cloud for the week forecast. However there are some gaps so got to go fishing! The solarquest mount saved the day again with it's super quick setup time; grabbing the mount out of the shed, mounting the Coronado SM40 ota on there and powering it up, by the time i'd nipped back inside to get my case with all the cameras etc it was pointing at the sun and tracking away. I used the Cemax 2x barlow to give me f20 on the Grasshopper GH3 91S6M camera. Only time for a couple of exposures in between the scudding clouds before the window closed again but i'm pleased how this came out. It's critically sampled for the 3.69um pixels and not sure I can get anymore detail at this scale. I'm optimistic the solarquest mount with take my (stripped back) Tal100R refractor for full disks at 60mm when the seeing allows.

CaK-FD-bw by Mark Townley, on Flickr

CaK-FD-colour by Mark Townley, on Flickr

Back to waiting for the gaps to appear!

Mark

[christian viladrich]

Excellent shoot !!

[Montana]

That's beautiful Mark, especially at 40mm

Just rain and clouds here today.

Alexandra

[Jordan Konisky]

I would like to expand my solar photography to include Ca-K imaging. My telescope is a SkyWatcher ED100 refractor. The Baader Ca-K filter would seem to be a good choice for me. It comes with a sheet of Baader AstroSolar film. I already own a Baader Astrozap filter so was wondering if the Astrozap filter could substitute for the AstroSolar film. Another option would be to pair the Ca-K filter with a Baader U filter. As always, any advice and suggestions would be greatly appreciated.

Jordan

[banjo]

Sans titre 1.gif (10.9 KiB) Viewed 232 times

[Montana]

Jordan, don't use the Baader U filter it passes light 320-380nm, therefore as CaK is 393nm you will not see anything! I can tell you from experience it is totally black.

The Baader CaK filter is 80A wide and therefore only really a subtle white light light filter which helps enhance faculae from the edge of the disc as seen in white light to the centre. It is not a traditional CaK filter like you see in Mark's image. Nigella has a good example of what it looks like. You must use it in conjunction with a white light filter, it is only a nosepiece filter and does not filter out the harsh rays of the Sun.

https://stargazerslounge.com/topic/3712 ... ader-ca-k/

Alexandra

[John]

That's a really super FD.

John

[marktownley]

Thanks for the kind words everyone! Yes, echo what Alexandra says, don't use the Venus filter, and, personally I wouldn't bother with the K-line either. Save up and get a Lunt CaK filter if you want to do calcium imaging.

[rsfoto]

Hi Mark,

Well done.

[DeepSolar64]

That is a beautiful well done CaK disc Mr. Townley. The sun is not very active but it's still nice.

[Carbon60]

Cracking FDs, Mark.

Stu.

[marktownley]

Thanks guys! expecting another day of dodging the showers and cloud tomorrow, fingers crossed Thursday afternoons forecast is more optimistic!

[EGRAY_OBSERVATORY]

Excellent Cak image Mark - well done

Terry

[justapictureposter]

That is a nice big picture! Did you use ROI at all , trim down the file size or is this with the full 9 megapixels enabled?

[marktownley]

Thanks Terry, thanks JAPP. No ROI, this is with full 9Mp resolution, just squared up in post processing.

[Stardust5858]

Lovely Mark, I missed the clear bit here, arrived to late.

[MapleRidge]

This is a superb CaK image Mark...excellent capture and processing

Brian

[DavidP]

Wow Mark. Very nice

[krakatoa1883]

Really great disc, Mark, superb.

[Jordan Konisky]

Mark,

By this you mean the Lunt CaK 2" star diagonal diagonal filter. Right? Is there any reason that it would not pair well with my Sky-Watcher Pro ED100? My 80th birthday arrives in April so perhaps I can coax it out of my family as a birthday gift. Thanks for your response to my post.

Jordan

[MapleRidge]

Jordan...

That style of filter will work with your 100mm scope...just choose the one that matches your scopes focal length. The B1200CaK would likely be the minimum to consider. You can get them with the diagonal or straight though version of the same blocking filter. Since these are an imaging filter the diagonal doesn't provide much advantage in my opinion.

Brian

[marktownley]

Mark,

By this you mean the Lunt CaK 2" star diagonal diagonal filter. Right? Is there any reason that it would not pair well with my Sky-Watcher Pro ED100? My 80th birthday arrives in April so perhaps I can coax it out of my family as a birthday gift. Thanks for your response to my post.

Jordan

Hi Jordan,

The ED100 is a good performer in CaK. Yes a Lunt diagonal, or, as Brian says the straight through module. B1200 as a minimum, consider stretching to the B1800.

Mark

[arnedanielsen]

Excellent catch, Mark.

The SolarQuest mount is fantastic for quick sessions like these!

Best regards,
Arne

[Jordan Konisky]

Thank you Mark. I see my way to stretching to the B1800.

Jordan

[marktownley]

Thank you Mark. I see my way to stretching to the B1800.

Jordan

You won't regret it!